This invention relates to an electrostatic device having a fixed and a variable electrode with an insulating layer positioned therebetween, and more particularly relates to such a device wherein the variable electrode is in the form of a roll.
A variety of electrostatic devices are known, especially those made for controlling the transmission or reflection of light by means of varying an electrical potential. Such devices generally take the form of a fixed electrode to which there is hingedly mounted a variable sheet or falp electrode that is caused to move toward and draw against the fixed electrode when an electrical potential is applied between the two electrodes.
The hinged geometry of these known devices imposes a practical limitation on the maximum size of the "aperture" of the light gates so made. Furthermore the hinged geometry devices are best suited for operation as fully closed or fully open whereas many applications for light gates exist requiring analog control of the aperture opening as a function of the applied potential.
It is therefore an object of the present invention to provide an electrostatic device having a large aperture.
It is a further object of the present invention to provide an electrostatic device adaptable for analog control of aperture opening as a function of applied potential.
It is yet a further object of the present invention to provide an electrically operable gate to various kinds of electromagnetic radiation having an essentially planar geometry and a wide aperture.